What are blockchain nodes?

What are blockchain nodes?

Blast Team

6 min read

When you start learning about blockchain technology, many new words and concepts start popping up, and it can be dazzling at first. If you look into definitions of a blockchain, most of the time, the term node will come up. Understanding what nodes are and what role they play is vital to understanding why a blockchain is secure and why we say it’s a decentralized network.

In this article we will look at what nodes are and what role they play in the architecture of a blockchain. Let’s start with defining what a blockchain is.

What is a blockchain?

We can define a blockchain as a decentralized public ledger managed by a peer-to-peer computer network, where nodes form part of a consensus algorithm protocol to add and validate transactions into blocks. Each transaction performed on a blockchain gets validated and recorded into a block. Each block then gets chained together with all the previous blocks to form a sort of chain. That’s why we call it a blockchain.

What do we mean by a decentralized peer-to-peer network? Well, hundreds or thousands of computers are connected to the internet and running 24/7 software to communicate with each other. Anyone can buy hardware, download the software and start running it to form a part of this network. This software, the protocol, is what defines how these computers share and maintain all the information needed for the public ledger. None of these devices own the whole truth; they all agree on what the truth is, and this is where decentralization comes from.

The devices running the software, validating transactions, and adding them to the blockchain are called nodes.

Why do we need blockchain nodes?

We already mentioned that blockchains are decentralized, meaning there is no central authority controlling what the truth is. When we talk about ‘the truth,’ we refer to the actual state of the public ledger that the blockchain is keeping. It wouldn’t make sense if someone could modify the balance in your wallet as they pleased or reject your valid transaction for any reason. 

Nodes are the source of truth of a blockchain, and they keep copies of the blockchain up to date. They work together, constantly sharing information and coming to a consensus regarding the state of the blockchain. Nodes are the core of the infrastructure of a blockchain and are responsible for making sure the rules set up for that blockchain are complied with.

Adoption helps decentralization because the more nodes a network has, the better the rules are maintained. If a network only had two nodes, for example, they could both come to an agreement and modify the state of the blockchain as they pleased. If thousands of nodes are distributed globally, they control one another and achieve a more decentralized state. This is the core idea of a blockchain being trustless; we don’t trust any central authority; we trust the decentralized network of nodes controlling each other.

Lastly, nodes are responsible for checking the validity of transactions and ensuring nobody is trying to make a non-valid transaction. The validity of a transaction varies from blockchain to blockchain since validity can mean many different things. One example could be someone trying to spend money they don’t own. There are many different ways a transaction can be invalid. Nodes check if a transaction is valid before adding it to the blockchain. If a transaction was added to a block, we know it was valid. There are exceptions to this, and waiting for a few blocks to be added to the blockchain after making a transaction helps us determine its validity. 

Nodes help to ensure that transactions are valid, consensus is maintained, decentralization is enabled, and security is upheld. Without nodes, a blockchain network would be unable to operate in a decentralized and secure manner.

Different blockchains, different nodes

As mentioned earlier, nodes play a crucial role in a blockchain’s operation. However, not all blockchains have the same type of nodes. Different blockchain networks have unique consensus algorithms that define how nodes in that particular network operate. As a result, different types of nodes may exist in different blockchain networks.

For example, Bitcoin’s consensus algorithm is proof-of-work (PoW). It requires nodes to compete against each other to solve a cryptographic puzzle to validate transactions and add them to the blockchain. This process requires high computational power, resulting in a particular type of node called miners. In PoW, miners compete with each other until one solves said cryptographic puzzle getting the right to publish the transactions to the blockchain and earning a reward in BTC. Miners are just one type of node in Bitcoins’ blockchain. There are several others that we’ll cover later in this article.

On the other hand, Ethereum uses a consensus algorithm called proof-of-stake (PoS), eliminating the need for miners. Instead, nodes called validators are responsible for validating transactions and adding them to the blockchain. Validators stake ETH to earn rewards and secure the network. The amount of stake plays a role in their chances of being selected to validate a block of transactions. If these validators misbehave, their stake might be slightly or entirely removed. Similar to Bitcoin, validators are not the only node type in Ethereum’s blockchain.

The type of consensus algorithm a blockchain uses can cause the network to have different types of nodes. While some blockchains may use similar consensus algorithms and have similar types of nodes, others may have entirely different node structures. When learning about a new blockchain and how it works, it is crucial to understand what consensus algorithm it uses and how the node structure is designed.

Types of nodes

The general goal of all nodes is to maintain the network. Still, we can classify them according to their specific functionalities. A single blockchain protocol can require multiple nodes, each fulfilling complementary roles in the network. Nodes can differ in their level of engagement in a blockchain protocol. While some nodes validate the entire block history, others contribute only a portion of the storage space. Therefore, not all nodes have the same level of responsibilities.

As blockchain technology continues to evolve and new use cases are discovered, the need for new blockchains and ways to solve challenges arise. Developers may need to create new types of nodes to address these issues. Not only this, but advances in technology may allow for new kinds of nodes that were not previously thought of. 

Below are a few types of nodes commonly used in Bitcoin, Ethereum, and other well-known blockchains.

  1. Full Nodes: Full nodes are responsible for verifying transactions and blocks, maintaining a copy of the entire blockchain, and broadcasting transactions to other nodes on the network. They play a critical role in ensuring the integrity and security of the blockchain network.
  1. Light Nodes: Light nodes are also known as SPV (Simplified Payment Verification) nodes. They don’t store a complete copy of the blockchain but rely on full nodes to verify transactions and blocks. Light nodes are commonly used in devices with limited storage capacity.
  1. Mining Nodes (PoW): Mining nodes create new blocks in the blockchain network. These nodes use specialized hardware and software to solve complex mathematical problems, which are used to validate transactions and create new blocks. They usually get rewarded when adding a block to the blockchain.
  1. Masternodes: Masternodes are nodes that perform specialized functions in a blockchain network. They do not add new blocks to the blockchain but instead only verify them. They also have particular managing, governing, and regulatory roles depending on the blockchain protocol they participate in
  1. Wallet Nodes: Wallet nodes manage cryptocurrency wallets and enable users to send and receive transactions on the blockchain network. They can be full nodes, light nodes, or a combination of both.
  1. Supernodes: Supernodes are high-performance nodes designed to handle large amounts of traffic on the blockchain network. They are commonly used in enterprise blockchain applications and other large-scale blockchain networks.

Overall, each type of node in a blockchain network plays a critical role in maintaining the network’s security, integrity, and functionality. 


Blockchain nodes are the core infrastructure of a blockchain network responsible for maintaining it, ensuring transactions are valid, and enforcing the protocol rules. Nodes work together to achieve consensus regarding the state of the blockchain. The more nodes a network has, the better the rules are enforced. 

Nodes are essential for decentralization and security, ensuring no central authority controls the network. Different blockchain networks have unique consensus algorithms and protocols, which define how nodes operate, resulting in various types of nodes. 

Participating as a node in a network of your interest helps promote decentralization and security and provides opportunities for earning rewards. Overall, understanding blockchain nodes’ role and importance in blockchain networks is essential for anyone looking to learn and get involved in the blockchain industry.

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